Water cleanable phase change ink for ophthalmic lens marking

ABSTRACT

A water dispersible phase change ink composition for printing on ophthalmic lenses including a hydrophilic wax having at least one ethoxyl moiety; a low viscosity wax having at least one hydroxyl group, wherein the low viscosity wax is miscible with the hydrophilic wax; an optional stabilizer; and a colorant. A ink jet printer stick or pellet comprising the water dispersible phase change ink composition.

TECHNICAL FIELD

Described herein are phase change inks suitable for use with ophthalmiclenses. More particularly described is a water dispersible phase changeink composition for printing on ophthalmic lenses comprising ahydrophilic wax having at least one ethoxyl moiety; a low viscosity waxhaving at least one hydroxyl group, wherein the low viscosity wax ismiscible with the hydrophilic wax; an optional stabilizer; and acolorant.

BACKGROUND

Disclosed herein is a phase change ink suitable for printing onophthalmic lenses. Ophthalmic lenses have been produced as semi-finishedlens by bulk lens manufacturers and then distributed to individuallaboratories to prepare the finished lens. Traditionally, labelinformation for each semi-finished lens was provided by printing therelevant information on a paper envelop for each lens.

Recently, lenses have been labeled by using a phase change ink to printthe relevant information directly onto the lens using a digital printer.However, current known phase change ink can exhibit performance issuesfor lens labeling applications including clogging of printer heads.Further performance issues include the need for jetting reliability,durability of the printed image on the lens, the need for printed imagesthat are removable from the lens when no longer needed thereon, and theneed for printed images on the lens that are of good print quality.Further, inks which require use of organic solvent in opticallaboratories for removing or cleaning of the ink on lens can beproblematic.

A need remains for an improved phase change ink suitable for printing onophthalmic lenses. Further, a need remains for an improved phase changeink suitable for printing on ophthalmic lenses which have improvedjetting reliability, improved durability after printing on lenses,provide printed images which are easy to clean and provide good adhesionon both hydrophilic and hydrophobic lenses, and which provide goodoptical contrast on both clear and dark lenses. Further, a need remainsfor an improved phase change ink suitable for printing on ophthalmiclenses wherein the printed images can be removed with water.

Throughout this application, various publications, patents, andpublished patent applications are referred to by an identifyingcitation. The disclosures of the publications, patents, and publishedpatent applications referenced in this application are herebyincorporated by reference into the present disclosure to more fullydescribe the state of the art to which this invention pertains.

SUMMARY

Described is a water dispersible phase change ink composition forprinting on ophthalmic lenses comprising a hydrophilic wax having atleast one ethoxyl moiety; a low viscosity wax having at least onehydroxyl group, wherein the low viscosity wax is miscible with thehydrophilic wax; an optional stabilizer; and a colorant.

Also described is an ink jet printer stick or pellet comprising a waterdispersible phase change ink composition for printing on ophthalmiclenses, wherein the phase change ink composition comprises a hydrophilicwax having at least one ethoxyl moiety; a low viscosity wax having atleast one hydroxyl group, wherein the low viscosity wax is miscible withthe hydrophilic wax; an optional stabilizer, wherein the optionalstabilizer, if present, is selected from the group consisting ofhindered amine, phenol, and mixtures and combinations thereof; and acolorant.

DETAILED DESCRIPTION

A water dispersible phase change ink composition is provided which isparticularly suitable for printing on ophthalmic lenses. In embodiments,the water dispersible phase change ink composition provides improvedjetting reliability, improved durability of the printed image afterprinting on lenses, printed images on the lenses which are easy to cleanand provide good adhesion on both hydrophilic and hydrophobic lenses,and good optical contrast on both clear and dark lenses. The waterdispersible phase change ink compositions provide robust printed imageson lenses and remain robust and intact images during lens shipment butcan be readily removed post-shipment as desired. In embodiments, thewater dispersible phase change ink composition is a water cleanable ink;that is, images printed with the water dispersible phase change inkcomposition can be removed with water.

In embodiments, a water dispersible phase change ink composition forprinting on ophthalmic lenses comprises a hydrophilic wax having atleast one ethoxyl moiety; a low viscosity wax having at least onehydroxyl group, wherein the low viscosity wax is miscible with thehydrophilic wax; an optional stabilizer; and a colorant.

In other embodiments, an ink jet printer stick or pellet comprising awater dispersible phase change ink composition for printing onophthalmic lenses, wherein the phase change ink composition comprises ahydrophilic wax having at least one ethoxyl moiety; a low viscosity waxhaving at least one hydroxyl group, wherein the low viscosity wax ismiscible with the hydrophilic wax; an optional stabilizer, wherein theoptional stabilizer, if present, is selected from the group consistingof an aromatic amine, hindered amine, phenol, and mixtures andcombinations thereof; and a colorant.

When used herein, a hydrophilic wax having at least one ethoxyl moietymeans that the hydrophilic wax has at least one group of the formula—(CH₂CH₂O)—.

When used herein, a low viscosity wax having at least one hydroxyl groupmeans that the low viscosity wax has at least one group of the formula—OH

In certain embodiments, water cleanable solid inks, in embodiments,yellow inks or black inks, are provided and are particularly suitablefor use in lens marking applications. The water dispersible phase changeink comprises a hydrophilic wax with ethoxyl moiety which provides theink with the characteristic of providing printed images that are readilyclean by water. In embodiments, low viscosity wax is selected as aviscosity modifier. The low viscosity wax has a hydroxyl group toprovide miscibility with the hydrophilic wax. In embodiments, astabilizer is included in the ink. The stabilizer provides good thermalstability by preventing oxidation of the hydroxyl group and possiblethermal degradation of the ethoxyl moiety.

The water dispersible phase change ink composition is water dispersibleat ambient temperature. The water dispersible phase change inkcomposition can be successfully jetted on to an ophthalmic lens. Theimages formed are durable, have good optical contrast, and are easilyremoved with water. The water dispersible phase change ink compositionexhibits good thermal stability of ink viscosity over time and goodjetting performance.

The water dispersible phase change ink composition includes ahydrophilic wax having at least one ethoxyl moiety. Any suitable ordesired hydrophilic wax can be selected in embodiments herein. Inembodiments, the hydrophilic wax is an ethoxylated alcohol.

In embodiments, the hydrophilic wax is an ethoxylated alcohol of theformulaCH₃—(CH₂CH₂)_(n)—(CH₂CH₂O)_(m)—H

wherein n is an integer and wherein m is an integer, and wherein n and mare each independently selected such that the total number of carbonatoms is from about 20 to about 50.

In embodiments, the hydrophilic wax is an ethoxylated alcohol, such asavailable from Petrolite and of the general formula

wherein x is an integer of from about 1 to about 50, such as from about5 to about 40 or from about 11 to about 24 and y is an integer of fromabout 1 to about 70, such as from about 1 to about 50 or from about 1 toabout 40. The materials may have a melting point of from about 60° C. toabout 150° C., such as from about 70° C. to about 120° C. or from about80° C. to about 110° C. and a molecular weight (Mn) range of from about100 to about 5,000, such as from about 500 to about 3,000 or from about500 to about 2,500. Commercial examples include UNITHOX 420 (Mn=560),UNITHOX 450 (Mn=900), UNITHOX 480 (Mn=2,250), UNITHOX 520 (Mn=700),UNITHOX 550 (Mn=1,100), UNITHOX 720 (Mn=875), UNITHOX 750 (Mn=1,400),and the like.

The hydrophilic wax can be present in the phase change ink compositionin any suitable or desired amount. In embodiments, the hydrophilic waxis present in an amount of from about 15 to about 85 percent by weight,or from about 20 to about 75 percent by weight, or from about 25 toabout 70 percent by weight, based upon the total weight of the phasechange ink composition. In certain embodiments, the hydrophilic wax ispresent in the phase change ink composition in an amount of greater thanabout 65 percent by weight, based upon the total weight of the phasechange ink composition.

The water dispersible phase change ink composition includes a lowviscosity wax having at least one hydroxyl group, wherein the lowviscosity wax is miscible with the hydrophilic wax. Any suitable ordesired low viscosity wax can be selected in embodiments herein. Inembodiments, the low viscosity wax is a wax having a viscosity of fromabout 1 to about 15, or from about 2 to about 13, or from about 3 toabout 10 centipoise at a temperature in the range of from about 80 toabout 120° C. In embodiments, the low viscosity wax is an alcohol wax.In embodiments, the low viscosity wax is selected from the groupconsisting of stearyl alcohol, behenyl alcohol, and mixtures andcombinations thereof. In embodiments, the low viscosity wax is behenylalcohol.

The low viscosity wax can be present in the phase change ink compositionin any suitable or desired amount. In embodiments, the low viscosity waxis present in an amount of from about 15 to about 75 percent by weight,or from about 20 to about 60 percent by weight, or from about 25 toabout 50 percent by weight, based upon the total weight of the phasechange ink composition.

In embodiments, the combined total amount of all wax present in thephase change, including both the hydrophilic wax and the low viscositywax along with any additional optional other wax, is from about 55 toabout 95 percent by weight, or from about 65 to about 90 percent byweight, or from about 75 to about 85 percent by weight, based upon thetotal weight of the phase change ink composition.

In embodiments, the water dispersible phase change ink compositionincludes an optional amide. Any suitable or desired amide can beselected for embodiments herein. In embodiments, the phase change inkcomposition comprises a fatty amide. The fatty amide can be any suitableor desired fatty amide. In embodiments, fatty amides herein includemonoamides, tetra-amides, mixtures thereof, and the like, for examplesuch as described in U.S. Pat. No. 6,858,070, which is herebyincorporated herein by reference.

In embodiments, the amide comprises a monoamide, a triamide, atetra-amide, or a mixture thereof. In embodiments, the amide comprise acombination of monoamide, triamide, and tetra-amide. Suitable monoamidesmay have a melting point of at least about 50° C., for example fromabout 50° C. to about 150° C., although the melting point can be outsidethese ranges. Specific examples of suitable monoamides include, forexample, primary monoamides and secondary monoamides. Stearamide, suchas KEMAMIDE® S available from Chemtura Corporation and CRODAMIDE® Savailable from Croda, behenamide/arachidamide, such as KEMAMIDE® Bavailable from Chemtura Corporation and CRODAMIDE® BR available fromCroda, oleamide, such as KEMAMIDE® U available from Chemtura Corporationand CRODAMIDE® OR available from Croda, technical grade oleamide, suchas KEMAMIDE® O available from Chemtura Corporation, CRODAMIDE® Oavailable from Croda, and UNISLIP® 1753 available from Uniqema, anderucamide such as KEMAMIDE® E available from Chemtura Corporation andCRODAMIDE® ER available from Croda, are some examples of suitableprimary amides. Behenyl behenamide, such as KEMAMIDE® EX666 availablefrom Chemtura Corporation, stearyl stearamide, such as KEMAMIDE® S-180and KEMAMIDE® EX-672 available from Chemtura Corporation, stearylerucamide, such as KEMAMIDE® E-180 available from Chemtura Corporationand CRODAMIDE® 212 available from Croda, erucyl erucamide, such asKEMAMIDE® E-221 available from Chemtura Corporation, oleyl palmitamide,such as KEMAMIDE® P-181 available from Chemtura Corporation andCRODAMIDE® 203 available from Croda, and erucyl stearamide, such asKEMAMIDE® S-221 available from Chemtura Corporation, are some examplesof suitable secondary amides. Additional suitable amide materialsinclude KEMAMIDE® W40 (N,N′-ethylenebisstearamide), KEMAMIDE® P181(oleyl palmitamide), KEMAMID®E W45 (N,N′-ethylenebisstearamide), andKEMAMIDE® W20 (N,N′-ethylenebisoleamide).

In embodiments, the amide can comprises a branched triamide. Branchedtriamides are disclosed in, for example, U.S. Pat. No. 6,860,930, thedisclosure of which is totally incorporated herein by reference. By“branched triamide” is meant that the structure of the triamide can bedrawn so that each amide group is bonded to an atom or group of atomscontained in a branch other than that of the others, and that each amidegroup is in a different branch. By “each amide group is in a differentbranch” is meant that the triamide is not linear; by “linear” is meant amolecule wherein all three amide groups can be drawn as being in thesame molecular chain or branch, such as linear triamides of the formulae

or the like. For purposes of the present invention, linear triamidesinclude those wherein a line can be drawn through the three amidegroups, even if one would ordinarily draw a different line. For example,a compound of the formula

is considered a linear compound for purposes of the present invention,because it can also be drawn as follows:

and accordingly would not be considered to be a branched triamide forthe purposes of the inks discloses herein. For purposes of the inksdisclosed herein, “branched triamines”, “branched triacids”, “branchedmonoamino diacids”, and “branched diamino monoacids” have similardefinitions in that each of the three functional groups named can bedrawn as being in a different branch from the other two.

Examples of suitable branched triamides include (but are not limited to)those generated from branched triamines, said branched triamides beingof the formula

wherein R₁ is (i) an alkylene group (including linear, branched,saturated, unsaturated, cyclic, acyclic, substituted, and unsubstitutedalkylene groups, and wherein hetero atoms, such as oxygen, nitrogen,sulfur, silicon, phosphorus, boron, and the like either may or may notbe present in the alkylene group), having from about 3 to about 200carbon atoms, (ii) an arylene group (including unsubstituted andsubstituted arylene groups, and wherein hetero atoms, as described abovemay optionally be present in the arylene group), having from about 6 toabout 200 carbon atoms, (iii) an arylalkylene group (includingunsubstituted and substituted arylalkylene groups, wherein the alkylportion of the arylalkylene group can be linear, branched, saturated,unsaturated, cyclic, and/or acyclic, and wherein hetero atoms, asdescribed above may optionally be present in either or both of the alkylportion and the aryl portion of the arylalkylene group), having fromabout 7 to about 200 carbon atoms, such as benzylene or the like, or(iv) an alkylarylene group (including unsubstituted and substitutedalkylarylene groups, wherein the alkyl portion of the alkylarylene groupcan be linear, branched, saturated, unsaturated, cyclic, and/or acyclic,and wherein hetero atoms, as described above may optionally be presentin either or both of the alkyl portion and the aryl portion of thealkylarylene group), having from about 7 to about 200 carbon atoms, suchas tolylene or the like, Ra, Rb, and Rc each, independently of theothers, is (i) a hydrogen atom, (ii) an alkyl group (including linear,branched, saturated, unsaturated, cyclic, acyclic, substituted, andunsubstituted alkyl groups, and wherein hetero atoms, such as describedabove may optionally be present in the alkyl group), having from 1carbon atom to about 200 carbon atoms, (iii) an aryl group (includingunsubstituted and substituted aryl groups, and wherein hetero atoms,such as described above may optionally be present in the aryl group),having from 6 to about 200 carbon atoms, (iv) an arylalkyl group(including unsubstituted and substituted arylalkyl groups, wherein thealkyl portion of the arylalkyl group can be linear, branched, saturated,unsaturated, cyclic, and/or acyclic, and wherein hetero atoms, such asdescribed above may optionally be present in either or both of the alkylportion and the aryl portion of the arylalkyl group), having from 6 toabout 200 carbon atoms, such as benzyl or the like, or (v) an alkylarylgroup (including unsubstituted and substituted alkylaryl groups, whereinthe alkyl portion of the alkylaryl group can be linear, branched,saturated, unsaturated, cyclic, and/or acyclic, and wherein heteroatoms, such as described above may optionally be present in either orboth of the alkyl portion and the aryl portion of the alkylaryl group),having 6 to about 200 carbon atoms, such as tolyl or the like, Rd, Re,and Rf each, independently of the others, is (i) an alkyl group(including linear, branched, saturated, unsaturated, cyclic, acyclic,substituted, and unsubstituted alkyl groups, and wherein hetero atoms,such as described above may optionally be present in the alkyl group),having 1 to about 200 carbon atoms, (ii) an aryl group (includingunsubstituted and substituted aryl groups, and wherein hetero atoms,such as described above may optionally be present in the aryl group),having 6 to about 200 carbon atoms, (iii) an arylalkyl group (includingunsubstituted and substituted arylalkyl groups, wherein the alkylportion of the arylalkyl group can be linear, branched, saturated,unsaturated, cyclic, and/or acyclic, and wherein hetero atoms, such asdescribed above may optionally be present in either or both of the alkylportion and the aryl portion of the arylalkyl group), having 6 to about200 carbon atoms, such as benzyl or the like, or (iv) an alkylaryl group(including unsubstituted and substituted alkylaryl groups, wherein thealkyl portion of the alkylaryl group can be linear, branched, saturated,unsaturated, cyclic, and/or acyclic, and wherein hetero atoms, such asdescribed above may optionally be present in either or both of the alkylportion and the aryl portion of the alkylaryl group), having 6 to about200 carbon atoms, such as tolyl or the like, those generated frombranched triacids, said branched triamides being of the formula

wherein R₂ is (i) an alkylene group as described for R₁ above, Rg, Rj,and Rp each, independently of the others, is (i) a hydrogen atom, (ii)an alkyl group (including linear, branched, saturated, unsaturated,cyclic, acyclic, substituted, and unsubstituted alkyl groups, andwherein hetero atoms may optionally be present in the alkyl group),having 1 to about 200 carbon atoms, (iii) an aryl group (includingunsubstituted and substituted aryl groups, and wherein hetero atoms mayoptionally be present in the aryl group), having 10 to about 200 carbonatoms, (iv) an arylalkyl group (including unsubstituted and substitutedarylalkyl groups, wherein the alkyl portion of the arylalkyl group canbe linear, branched, saturated, unsaturated, cyclic, and/or acyclic, andwherein hetero atoms may optionally be present in either or both of thealkyl portion and the aryl portion of the arylalkyl group), having 7 toabout 200 carbon atoms, such as benzyl or the like, or (v) an alkylarylgroup (including unsubstituted and substituted alkylaryl groups, whereinthe alkyl portion of the alkylaryl group can be linear, branched,saturated, unsaturated, cyclic, and/or acyclic, and wherein hetero atomsmay optionally be present in either or both of the alkyl portion and thearyl portion of the alkylaryl group), having 7 to about 200 carbonatoms, such as tolyl or the like, Rh, Rk, and Rq each, independently ofthe others, is (i) a hydrogen atom, (ii) an alkyl group (includinglinear, branched, saturated, unsaturated, cyclic, acyclic, substituted,and unsubstituted alkyl groups, and wherein hetero atoms may optionallybe present in the alkyl group), having 1 to about 200 carbon atoms,(iii) an aryl group (including unsubstituted and substituted arylgroups, and wherein hetero atoms may optionally be present in the arylgroup), having 6 to about 200 carbon atoms, (iv) an arylalkyl group(including unsubstituted and substituted arylalkyl groups, wherein thealkyl portion of the arylalkyl group can be linear, branched, saturated,unsaturated, cyclic, and/or acyclic, and wherein hetero atoms mayoptionally be present in either or both of the alkyl portion and thearyl portion of the arylalkyl group), having 7 to about 200 carbon atomssuch as benzyl or the like, or (v) an alkylaryl group (includingunsubstituted and substituted alkylaryl groups, wherein the alkylportion of the alkylaryl group can be linear, branched, saturated,unsaturated, cyclic, and/or acyclic, and wherein hetero atoms mayoptionally be present in either or both of the alkyl portion and thearyl portion of the alkylaryl group), having 7 to about 200 carbonatoms, such as tolyl or the like, those generated from branched diaminomonoacid compounds, said branched triamides being of the formula

wherein R₁, Ra, Rb, Rd, Re, Rg, and Rh are as defined hereinabove, thosegenerated from branched monoamino diacid compounds, said branchedtriamides being of the formula

wherein R₂, Ra, Rd, Rg, Rh, Rj, and Rk are as defined hereinabove, andthe like, wherein the substituents on the substituted alkyl, alkylene,aryl, arylene, arylalkyl, arylalkylene, alkylaryl, and alkylarylenegroups can be (but are not limited to) hydroxy groups, halogen atoms,imine groups, ammonium groups, cyano groups, pyridine groups, pyridiniumgroups, ether groups, aldehyde groups, ketone groups, ester groups,carbonyl groups, thiocarbonyl groups, sulfate groups, sulfonate groups,sulfonic acid groups, sulfide groups, sulfoxide groups, phosphinegroups, phosphonium groups, phosphate groups, nitrile groups, mercaptogroups, nitro groups, nitroso groups, sulfone groups, azide groups, azogroups, cyanato groups, carboxylate groups, mixtures thereof, and thelike, wherein two or more substituents can be joined together to form aring.

In one specific embodiment, when the triamide is of the formula

the total number of carbon atoms in R₁+Ra+Rb+Rc+Rd+Re+Rf is 7 to no morethan about 500. In another specific embodiment, each of Ra, Rd, Rb, Re,Rc, and Rf, independently of the others, has no more than about 50carbon atoms, and in yet another specific embodiment no more than about48 carbon atoms, although the number of carbon atoms can be outside ofthese ranges.

In one specific embodiment, when the triamide is of the formula

the total number of carbon atoms in R₂+Rg+Rh+Rj+Rk+Rp+Rq is about 7 tono more than about 500. In another specific embodiment, each of Rg, Rh,Rj, Rk, Rp, and Rq, independently of the others, has no more than about50 carbon atoms, and in yet another specific embodiment no more thanabout 48 carbon atoms, although the number of carbon atoms can beoutside of these ranges.

In one specific embodiment, when the triamide is of the formula

the total number of carbon atoms in R₁+Ra+Rb+Rd+Re+Rg+Rh is about 7 tono more than about 500. In another specific embodiment, each of Ra, Rd,Rb, Re, Rg, and Rh, independently of the others, has no more than about50 carbon atoms, and in yet another specific embodiment no more thanabout 48 carbon atoms, although the number of carbon atoms can beoutside of these ranges.

In one specific embodiment, when the triamide is of the formula

the total number of carbon atoms in R₂+Ra+Rd+Rg+Rh+Rj+Rk is about 7 tono more than about 500. In another specific embodiment, each of Ra, Rd,Rg, Rh, Rj, and Rk, independently of the others, has no more than about50 carbon atoms, and in yet another specific embodiment no more thanabout 48 carbon atoms, although the number of carbon atoms can beoutside of these ranges.

It must be emphasized that not all of the amide groups in the firstformula need to be directly bonded to the same atom in the R₁ or R₂group, and in one specific embodiment, each amide group is bonded to adifferent atom in the R₁ or R₂ group.

In one specific embodiment, the branched triamide is of the formula

wherein x, y, and z each, independently represent the number ofpropyleneoxy repeat units and x+y+z is from about 5 to about 6, andwherein p, q, and r each, independently of the others, are integersrepresenting the number of repeat —(CH₂)— units and are from about 15 toabout 60. The triamide composition is frequently obtained as a mixtureof materials, wherein p, q, and r are each peak average chain lengthnumbers within the composition, rather than uniform compositions whereineach molecule has the same value for p, q, and r, and it must beunderstood that within the mixture, some individual chains may be longeror shorter than the given numbers.

A triamide wax can be prepared as described in Example II of U.S. Pat.No. 6,860,930, is prepared as follows. To a 1,000 milliliter four-neckround bottom flask fitted with a Trubore stirrer, N₂ inlet, Dean-Starktrap with condenser and N₂ outlet and thermocouple-temperaturecontroller was added 350.62 grams (0.3675 moles) of UNICID® 550 (amono-acid obtained from Baker-Petrolite Corp., Cincinnati, Ohio, of theformula CH₃(CH₂)_(n)COOH, wherein n has an average value of about 37 andis believed to have a range of from about 34 to about 40) and 0.79 gramsof NAUGARD® 524 (antioxidant obtained from Uniroyal Chemical Company,Inc., Middlebury, Conn.). The mixture was heated to 115° C. to melt, andstirred at atmospheric pressure under N₂. 51.33 grams (0.1167 moles) ofJEFFAMINE® T-403 (mixture of triamines obtained from HuntsmanCorporation, Houston, Tex., of the formula

wherein x, y, and z are each integers representing the number of repeatpropyleneoxy units, wherein x, y, and z may each be zero, and whereinthe sum of x+y+z is from about 5 to about 6) was then added to thereaction mixture, and the reaction temperature was increased to 200° C.gradually over 0.5 hour and held at that temperature for another 3hours. Some water was carried out by slow blowing N₂ and condensed intothe trap when the mixture temperature reached about 180° C. The trap andcondenser were then removed, and vacuum (about 25 mm Hg) was applied forabout 0.5 hour and then released. The liquid product was cooled down toabout 150° C. and poured onto aluminum to solidify. The resultingproduct was believed to be of the formula

wherein n, x, y, and z are as defined hereinabove.

In embodiments, the amide selected is a triamide. The triamide canprovide the feature of low viscosity compared to using a tetra-amide forthe same molecular weight. In a specific embodiment, the amide is abranched triamide

The amide can be present in the phase change ink composition in anysuitable or desired amount. In embodiments, the amide is present in anamount of from about 0.5 to about 10 percent by weight, or from about 1to about 8 percent by weight, or from about 2 to about 6 percent byweight, based upon the total weight of the phase change ink composition.

The water dispersible phase change ink composition can further comprisea stabilizer. Any suitable or desired stabilizer can be selected inembodiments herein. In embodiments, the stabilizer is selected from thegroup consisting of hindered amine, phenol, an aromatic amineantioxidant stabilizer, and mixtures and combinations thereof.

The stabilizer can be present in the phase change ink composition in anysuitable or desired amount. In embodiments, the stabilizer is present inan amount of from about 0.05 to about 3 percent by weight, or from about0.1 to about 2 percent by weight, or from about 0.2 to about 1 percentby weight, based upon the total weight of the phase change inkcomposition.

The ink may further include conventional additives to take advantage ofthe known functionality associated with such conventional additives.Such additives may include, for example, at least one antioxidant,defoamer, slip and leveling agents, clarifier, viscosity modifier,adhesive, plasticizer and the like. In embodiments, the phase change inkcomposition includes a member of the group consisting of plasticizer,stabilizer, antioxidant, defoamer, slip and leveling agents, clarifier,viscosity modifier, adhesive, and mixtures and combinations thereof.

The ink may optionally contain antioxidants to protect the images fromoxidation and also may protect the ink components from oxidation whileexisting as a heated melt in the ink reservoir. Examples of suitableantioxidants include N,N′-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide) (IRGANOX® 1098, available from BASF);2,2-bis(4-(2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl)propane (TOPANOL-205, available from Vertellus);tris(4-tert-butyl-3-hydroxy-2,6-dimethyl benzyl)isocyanurate (Aldrich);2,2′-ethylidene bis(4,6-di-tert-butylphenyl)fluoro phosphonite (ETHANOX®398, available from Albermarle Corporation);tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenyl diphosphonite (Aldrich);pentaerythritol tetrastearate (TCI America); tributylammoniumhypophosphite (Aldrich); 2,6-di-tert-butyl-4-methoxyphenol (Aldrich);2,4-di-tert-butyl-6-(4-methoxybenzyl)phenol (Aldrich);4-bromo-2,6-dimethylphenol (Aldrich); 4-bromo-3,5-didimethylphenol(Aldrich); 4-bromo-2-nitrophenol (Aldrich); 4-(diethylaminomethyl)-2,5-dimethylphenol (Aldrich); 3-dimethylaminophenol(Aldrich); 2-amino-4-tert-amylphenol (Aldrich);2,6-bis(hydroxymethyl)-p-cresol (Aldrich); 2,2′-methylenediphenol(Aldrich); 5-(diethylamino)-2-nitrosophenol (Aldrich);2,6-dichloro-4-fluorophenol (Aldrich); 2,6-dibromo fluoro phenol(Aldrich); α-trifluoro-o-cresol (Aldrich); 2-bromo-4-fluorophenol(Aldrich); 4-fluorophenol (Aldrich);4-chlorophenyl-2-chloro-1,1,2-tri-fluoroethyl sulfone (Aldrich);3,4-difluoro phenylacetic acid (Aldrich); 3-fluorophenyl acetic acid(Aldrich); 3,5-difluoro phenylacetic acid (Aldrich);2-fluorophenylacetic acid (Aldrich); 2,5-bis (trifluoromethyl) benzoicacid (Aldrich);ethyl-2-(4-(4-(trifluoromethyl)phenoxy)phenoxy)propionate (Aldrich);tetrakis (2,4-di-tert-butyl phenyl)-4,4′-biphenyl diphosphonite(Aldrich); 4-tert-amyl phenol (Aldrich);3-(2H-benzotriazol-2-yl)-4-hydroxy phenethylalcohol (Aldrich); NAUGARD®76, NAUGARD® 445, NAUGARD® 512, and NAUGARD® 524 (manufactured byChemtura Corporation); and the like, as well as mixtures thereof. Theantioxidant, when present, may be present in the ink in any desired oreffective amount, such as from about 0.25 percent to about 10 percent byweight of the ink or from about 1 percent to about 5 percent by weightof the ink.

The water dispersible phase change ink composition can further comprisea colorant. Any suitable or desired colorant including dyes, pigments,and mixtures and combinations thereof can be selected. In embodiments,the colorant is selected from the group consisting of dyes, pigments,and mixtures and combinations thereof. In specific embodiments, thecolorant is a dye. In other embodiments, the colorant is a pigment. Incertain embodiments, the colorant is a yellow dye. In certain otherembodiments, the colorant is a black dye.

Any desired or effective colorant can be employed in the inks, includingdyes, pigments, mixtures thereof, and the like, provided that thecolorant can be dissolved or dispersed in the ink vehicle. Thecompositions can be used in combination with conventional ink colorantmaterials, such as Color Index (C.I.) Solvent Dyes, Disperse Dyes,modified Acid and Direct Dyes, Basic Dyes, Sulphur Dyes, Vat Dyes, andthe like.

Examples of suitable dyes include Neozapon® Red 492 (BASF); Orasol® RedG (Pylam Products); Direct Brilliant Pink B (Oriental Giant Dyes);Direct Red 3BL (Classic Dyestuffs); Supranol® Brilliant Red 3BW (BayerAG); Lemon Yellow 6G (United Chemie); Light Fast Yellow 3G (Shaanxi);Aizen Spilon Yellow C-GNH (Hodogaya Chemical); Bemachrome Yellow GD Sub(Classic Dyestuffs); Cartasol® Brilliant Yellow 4GF (Clariant); CibanoneYellow 2G (Classic Dyestuffs); Orasol® Black RLI (BASF); Orasol® BlackCN (Pylam Products); Savinyl Black RLSN (Clariant); Pyrazol Black BG(Clariant); Morfast® Black 101 (Rohm & Haas); Diaazol Black RN (ICI);Thermoplast® Blue 670 (BASF); Orasol® Blue GN (Pylam Products); SavinylBlue GLS (Clariant); Luxol Fast Blue MBSN (Pylam Products); Sevron Blue5GMF (Classic Dyestuffs); Basacid® Blue 750 (BASF); Keyplast Blue(Keystone Aniline Corporation); Neozapon® Black X51 (BASF); ClassicSolvent Black 7 (Classic Dyestuffs); Sudan Blue 670 (C.I. 61554) (BASF);Sudan Yellow 146 (C.I. 12700) (BASF); Sudan Red 462 (C.I. 26050) (BASF);C.I. Disperse Yellow 238; Neptune Red Base NB543 (BASF, C.I. Solvent Red49); Neopen® Blue FF-4012 (BASF); Fastol® Black BR (C.I. Solvent Black35) (Chemische Fabriek Triade BV); Morton Morplas Magenta 36 (C.I.Solvent Red 172); metal phthalocyanine colorants, such as thosedisclosed in U.S. Pat. No. 6,221,137, the disclosure of which is totallyincorporated herein by reference, and the like. Polymeric dyes can alsobe used, such as those disclosed in, for example, U.S. Pat. No.5,621,022 and U.S. Pat. No. 5,231,135, the disclosures of each of whichare hereby incorporated by reference herein in their entireties, andcommercially available from, for example, Milliken & Company as MillikenInk Yellow 869, Milliken Ink Blue 92, Milliken Ink Red 357, Milliken InkYellow 1800, Milliken Ink Black 8915-67, uncut Reactint® Orange X-38,uncut Reactint® Blue X-17, Solvent Yellow 162, Acid Red 52, Solvent Blue44, and uncut Reactint® Violet X-80.

In embodiments, the colorant comprises a yellow dye. In otherembodiments, the colorant comprises a black dye. In embodiments, thecolorant is an azo pyridone colorant as described in U.S. Pat. No.6,590,082, which is hereby incorporated by reference herein in itsentirety. In embodiments, the colorant is an azo pyridone colorant asdescribed in U.S. Pat. No. 7,294,730, which is hereby incorporated byreference herein in its entirety.

The colorant is present in the ink in any desired or effective amount,in embodiments the colorant is present in an amount of from about 0.1 toabout 10 percent, or from about 0.2 to about 7 percent, or from about0.5 to about 5 percent by weight based upon the total weight of the ink.

The water dispersible phase change ink compositions here in optionallyfurther comprise a synergist. Any suitable or desired synergist can beemployed. In embodiments, a copper phthalocyanine derivative is employedas a synergist for improving dispersion stability of pigmented phasechange inks.

The water dispersible phase change ink compositions herein can contain adispersant. Any suitable or desired dispersant can be employed. Inembodiments, the dispersant can be a dispersant described in U.S. Pat.No. 7,973,186 of Adela Goredema, et al., which is hereby incorporated byreference herein in its entirety. In specific embodiments, thedispersant is a compound of the formula

or a mixture thereof; wherein R and R′ are the same or different, andwherein R and R′ are independently selected from a linear alkyl grouphaving about 37 carbon atoms and a linear alkyl group having about 47carbon atoms; and wherein m is an integer of from about 1 to about 30.

The dispersant can optionally be a polymeric dispersant such as thosesold under the name Solsperse®, in embodiments, Solsperse® 1700,Solsperse® 32000, Solsperse® 13240, available from The LubrizolCorporation.

The dispersant can be provided in the phase change ink composition inany suitable or desired amount. In embodiments, the dispersant can bepresent in an amount of from about 1 to about 500 percent, or from about10 to about 300 percent, or from about 30 to about 200 percent totaldispersant, based on the total weight of the pigment in the phase changeink composition.

The water dispersible phase ink compositions can be prepared by anydesired or suitable method. For example, the ink ingredients can bemixed together, followed by heating, to a temperature of at least about100° C. to no more than about 140° C., although the temperature can beoutside of this range, and stiffing until a homogeneous ink compositionis obtained, followed by cooling the ink to ambient temperature(typically from about 20 to about 25° C.). The inks of the presentdisclosure are solid at ambient temperature. In a specific embodiment,during the formation process, the inks in their molten state are pouredinto molds and then allowed to cool and solidify to form ink sticks.

In embodiments, an ink jet printer stick or pellet herein comprises awater dispersible phase change ink composition for printing onophthalmic lenses, the water dispersible phase change ink compositioncomprising a hydrophilic wax having at least one ethoxyl moiety; a lowviscosity wax having at least one hydroxyl group, wherein the lowviscosity wax is miscible with the hydrophilic wax; an optionalstabilizer, wherein the optional stabilizer, if present, is selectedfrom the group consisting of hindered amine, phenol, and mixtures andcombinations thereof; and a colorant.

A water dispersible phase change ink composition is provided having aparticular combination and relative ratio of selected components. Inembodiments, the particular combination comprises a combination of bothhydrophilic wax and low viscosity wax which is miscible with thehydrophilic wax, an optional stabilizer, in embodiments, an amide, and acolorant. The present inventors have found that this particularcombination and ratio of ingredients provides improved properties ofjetting reliability, improved durability after printing on lenses,printed images on the lenses which are easy to clean, can be removedwith water, and provide good adhesion on both hydrophilic andhydrophobic lenses, and good optical contrast on both clear and darklenses.

The inks disclosed herein can be employed in apparatus for directprinting ink jet processes and in indirect (offset) printing ink jetapplications. Another embodiment is directed to a process whichcomprises incorporating an ink as disclosed herein into an ink jetprinting apparatus, melting the ink, and causing droplets of the meltedink to be ejected in an imagewise pattern onto a recording substrate. Adirect printing process is also disclosed in, for example, U.S. Pat. No.5,195,430, the disclosure of which is totally incorporated herein byreference. The inks prepared as disclosed herein can be employed inapparatus for indirect (offset) printing ink jet applications. Anotherembodiment is directed to a process which comprises incorporating an inkprepared as disclosed herein into an ink jet printing apparatus, meltingthe ink, causing droplets of the melted ink to be ejected in animagewise pattern onto an intermediate transfer member, and transferringthe ink in the imagewise pattern from the intermediate transfer memberto a final recording substrate. In a specific embodiment, theintermediate transfer member is heated to a temperature above that ofthe final recording sheet and below that of the melted ink in theprinting apparatus. An offset or indirect printing process is alsodisclosed in, for example, U.S. Pat. No. 5,389,958, the disclosure ofwhich is totally incorporated herein by reference. In one specificembodiment, the printing apparatus employs a piezoelectric printingprocess wherein droplets of the ink are caused to be ejected inimagewise pattern by oscillations of piezoelectric vibrating elements.

In embodiments, a method herein comprises incorporating into an ink jetprinting apparatus a phase change ink composition as described herein;melting the ink composition; and causing droplets of the melted ink tobe ejected in an imagewise pattern onto a substrate.

Ink jetting temperature can be any suitable or desired jettingtemperature, in embodiments, jetting temperature being from about 50° C.to about 150° C. or from about 50° C. to about 140° C. or more typicallyfrom about 100° C. to about 140° C. The ink compositions generally havemelt viscosities at the jetting temperature (in one embodiment no lowerthan about 50° C., in another embodiment no lower than about 60° C., andin yet another embodiment no lower than about 70° C., and in oneembodiment no higher than about 150° C., and in another embodiment nohigher than about 145° C., although the jetting temperature can beoutside of these ranges) in one embodiment of no more than about 30centipoise, in another embodiment of no more than about 20 centipoise,and in yet another embodiment of no more than about 15 centipoise, andin one embodiment of no less than about 2 centipoise, in anotherembodiment of no less than about 5 centipoise, and in yet anotherembodiment of no less than about 7 centipoise, in another embodiment, ofgreater than about 10⁵ centipoise at a temperature of less than about40° C., in another embodiment, of less than about 15 centipoise at atemperature of no less than about 70° C., although the melt viscositycan be outside of these ranges.

In one specific embodiment, the inks are jetted at low temperatures, inparticular at temperatures below about 150° C., in one embodiment fromabout 40° C. to about 150° C., in another embodiment from about 50° C.to about 145° C., and in yet another embodiment from about 60° C. toabout 125° C., although the jetting temperature can be outside of theseranges.

In a specific embodiment, the ink compositions herein are jetted onto anophthalmic lens. The ophthalmic lens may be coated with a hydrophiliccoating or a hydrophobic coating. For example, the ink compositionsherein are suitable for printing images on lenses such as thosecommercially available from Essilor International SA (France). The lenscan be a glass or an organic ophthalmic lens. The lens can be a polymercomposition lens such as injection molded polycarbonate or thermosetcast CR-39®. The lens can be coated, for example with an anti-reflectiveor other coating.

EXAMPLES

The following Examples are being submitted to further define variousspecies of the present disclosure. These Examples are intended to beillustrative only and are not intended to limit the scope of the presentdisclosure. Also, parts and percentages are by weight unless otherwiseindicated.

Inks. Ink Examples were prepared having the components provided inTables 1 and 2. The inks were prepared by combining the components inthe amounts shown in Table 1 in a beaker fitted with magnetic stirringand heating, heating to a temperature of about 130° C. and stirring fora period of about 2 hours. The inks were then filtered thru a 1 μmfilter paper to give the desired ink.

TABLE 1 1 Example (Control) Ink Color Yellow Component Polywax ® 22.03655 Microsere ® 20.55 5714A Wax Pinecrystal ™ 15.03 KE-311 Triamide20.03 Wax Kemamide ® 20.54 S-180 Yellow Dye 1.82 TOTAL 100 (weightpercent)

TABLE 2 Example 1 (Control) 2 3 Component Weight Percent Weight PercentWeight Percent Behenyl Alcohol 29.33 27.94 Unithox ™ 550 68.45 65.19Triamide Wax -0- 4.66 Yellow Dye 1.82 1.82 Naugard ® 445 0.40 0.40 Total100 100

Polywax® 655 is a hydrocarbon based wax that is a homopolymer ofpolyethylene (Mn about 655) of the general formula

wherein x is an integer of from 1 to 200, commercially available fromBaker Petrolite.

Microsere® 5714A Wax is a microcrystalline wax commercially availablefrom Alfa Chemicals Ltd.

Pinecrystal™ KE-311 is a triglyceride of hydrogenated abietic (rosin)acid commercially available from Arakawa Chemical Industries, Ltd.

Kemamide® S-180 is stearyl stearamide available from ChemturaCorporation.

Behenyl alcohol, CH₃(CH₂)₂₀CH₂OH, low viscosity wax, was obtained asNACOL® 22-98, from Sasol North America Inc., Westlake, La.

Unithox™ 550, a hydrophilic wax of the formulaCH₃—(CH₂CH₂)_(n)—(CH₂CH₂O)_(m)—H, obtained from Baker Hughes.

A triamide wax prepared as described in Example II of U.S. Pat. No.6,860,930, is prepared as follows. To a 1,000 milliliter four-neck roundbottom flask fitted with a Trubore stirrer, N₂ inlet, Dean-Stark trapwith condenser and N₂ outlet and thermocouple-temperature controller wasadded 350.62 grams (0.3675 moles) of UNICID® 550 (a mono-acid obtainedfrom Baker-Petrolite Corp., Cincinnati, Ohio, of the formulaCH3(CH2)nCOOH, wherein n has an average value of about 37 and isbelieved to have a range of from about 34 to about 40) and 0.79 grams ofNAUGARD® 524 (Chemtura Corporation). The mixture was heated to 115° C.to melt, and stirred at atmospheric pressure under N₂. 51.33 grams(0.1167 moles) of JEFFAMINE® T-403 (mixture of triamines obtained fromHuntsman Corporation, Houston, Tex., of the formula

wherein x, y, and z are each integers representing the number of repeatpropyleneoxy units, wherein x, y, and z may each be zero, and whereinthe sum of x+y+z is from about 5 to about 6) was then added to thereaction mixture, and the reaction temperature was increased to 200° C.gradually over 0.5 hour and held at that temperature for another 3hours. Some water was carried out by slow blowing N₂ and condensed intothe trap when the mixture temperature reached about 180° C. The trap andcondenser were then removed, and vacuum (about 25 mm Hg) was applied forabout 0.5 hour and then released. The liquid product was cooled down toabout 150° C. and poured onto aluminum to solidify. The resultingproduct was believed to be of the formula

wherein n, x, y, and z are as defined hereinabove in this Example.

Yellow dye comprising a colorant of the formula

was prepared as described in Example II of U.S. Pat. No. 6,590,082,which is hereby incorporated by reference herein in its entirety. Amixture of octadecanol (270 grams, 1.0 mol; obtained from Sigma-AldrichCo., Milwaukee, Wis.), isatoic anhydride (24 grams, 1.5 mol; obtainedfrom Sigma-Aldrich Co.), and 1,4-diazabicyclo[2.2.2]octane (56 grams,0.50 mol; obtained from Sigma-Aldrich Co.) in 1,000 milliliters ofdimethylformamide was stirred and heated to 100° C. in a 4 liter beaker.Vigorous gas evolution occurred. After 10 minutes, the resultant brownsolution was heated to 150° C. for 15 minutes. The reaction mixture wasthen cooled to 50° C. and vigorously stirred while 3,000 milliliters ofmethanol was added. The resultant suspension was stirred for 0.5 hourfollowed by vacuum filtration. The solid thus obtained was washed in thefilter funnel with 4×300 milliliter portions of methanol and then driedin air to give the product stearyl anthranilate as white power (330.5grams, 85 percent yield).

N-stearyl pyridone was prepared as follows. Into a 2 liter flaskequipped with stirrer and temperature thermostat was chargedoctadecylamine (stearylamine, 18.9 grams, 0.07 mol; obtained fromSigma-Aldrich Co.) followed with ethyl cyanoacetate (7.9 grams, 0.07mol; obtained from Spectrum Chemicals, New Brunswick, N.J.). Theresulting mixture was stirred and heated to 120° C. internal temperaturefor 1 hour. To the hot reaction mixture was then sequentially addedethyl acetoacetate (10.08 grams, 0.0775 mol; obtained from Lonza Group,Group), piperidine (11.0 grams, 0.13 mol; obtained from Sigma-AldrichCo.), and 60 milliliters of a solvent mixture containing 5 parts byweight toluene and 1 part by weight 1,2-dimethoxyethane. The reactionproceeded at 120° C. for another 24 hours. The solvents were thenremoved by distillation in vacuo, and the remaining viscous liquid wascarefully poured into a solution of methanol (80 milliliters), deionizedwater (20 milliliters), and concentrated hydrochloric acid (16milliliters, 2.5 mol). A solid precipitate formed instantly and theslurry was vacuum filtered followed by rinsing the solid cake with 2×50milliliter portions of 80 percent aqueous methanol. The cake thusobtained was air-dried for 24 hours to afford 24.5 grams (0.061 mol, 87percent yield) of N-stearyl pyridine produce as light tan power.

Into a 1 liter round-bottom flask equipped with stirrer and thermometerwas charged stearyl anthranilate (136.4 grams, 0.35 mol), glacial aceticacid (145 grams), dodecylbenzene sulfonic acid (16 grams; obtained fromStepan Chemicals as Biosoft® S-101, Northfield, Ill.), and distilledwater (28 grams). After complete dissolution of the stearylanthranilate, the resulting mixture was chilled in an ice bath to atemperature of 5 to 10° C. Thereafter, nitrosylsulfuric (NSA)(commercial solution containing 40 percent by weight NSA in sulfuricacid, obtained from Sigma-Aldrich Co.; 114.4 grams, 0.36 mol) was addeddropwise at such a rate that the solution temperature did not exceed 15°C. This reaction resulted in formation of the corresponding diazoniumsalt. The residual excess NSA was then quenched by addition of sulfamicacid.

Into a 10 liter beaker fitted with mechanical stirrer was chargedstearyl pyridone (201.3 grams, 0.5 mol), distilled water (4 liters),sodium hydroxide (100 grams, 2.5 mol), sodium acetate (287.18 grams, 3.5mol), and isopropyl alcohol (2 liters). The solution was stirred wellfor 30 minutes. The cloudy solution was then filtered through a Whatman#4 filter paper and the filtrate was returned to the 10 liter beaker.

The cold diazonium salt solution was poured slowly into the pyridonesolution, resulting in the immediate formation of a bright yellowprecipitate. After stirring for 30 minutes, the precipitate wasvacuum-filtered. The yellow solid was then washed extensively withdistilled water by the process of re-dispersing the solid into 4 literportions of water and filtering, repeating the process until theconductivity of the filtrate was low. The solid was then rinsed withmethanol (3 liters) and dried at 40° C. to give a final dry yield of217.2 grams (79 percent) as a bright yellow power.

Naugard® 445 is an aromatic amine antioxidant stabilizer, 4,4′-Bis(α,α-dimethylbenzyl) diphenylamine, commercially available from ChemturaCorporation.

The inks were characterized as follows.

TABLE 3 Example 1 (Control) 2 3 Ink Properties Weight Percent WeightPercent Weight Percent Visc. at 110° C. — 12.21 13.03 Visc. at 125° C.11.38 — 9.75 Visc. at 130° C. — 8.44 8.94 Spectral Strength in TolueneUnfiltered Ink at 990 995 985 431 nanometers Filtered Ink at 431 989 992989 nanometers Peak Melting Point 84.7 67.8 66.8 (° C.) by DSC PeakFreezing Point 75.8 59.9 58.2 (° C.) by DSC

The viscosity properties of the material were determined at using a 50millimeter cone and plate geometry on an AR 1000 Rheometer, obtainedfrom Rheometrics Corporation, now TA Instruments, Inc.

DSC: Melting point was measured by Differential Scanning calorimetryusing a DuPont 2100 calorimeter at a scan rate of 10° C./minute.

Thermal stabilities of the inks were tested by cooking the inks in glassjars in an over at 125° C., and then monitoring the viscosity change.The results as shown in Table 4 illustrate very good thermal stabilityof the viscosity after cooking for up to 6 to 9 days at 125° C., whichis a desirable feature for reliable jetting performance. Viscosity meanscentipoise at 110° C. and 125° C.

TABLE 4 Days at 125° C. Example Properties 0 1 2 5 6 9 2 Visc. at 12.2112.22 12.16 12.23 12.22 — 110° C. 3 Visc. at 13.03 13.10 13.00 12.9813.10 — 110° C. 3 Visc. at  9.75  9.73  9.75  9.73  9.76 9.76 125° C.

Further, the inks herein showed desirable Newtonian behavior forviscosity when scanning over different frequencies.

The inks of Examples 2 and 3 showed good jetting performance at 125° C.The ink of Example 2 jetted onto a lens can survive a durability test inwhich the lens having an ink image jetted thereon was put into a paperenvelop, the imaged lens containing envelope shaken, then checked todetermine if there was any ink shaken off after shaking the envelope.There was not. The ink of Example 2 jetted onto the lens can be easilyremoved by spraying water on the lens and then wiping with a cloth, thusdemonstrating ease of cleaning with water. One gram of the ink ofExample 2 or Example 3 can be easily dispersible into 60 milliliters ofwater after standing still overnight, whereas 1 gram of the Control inkof Example 1 was not dispersible at all in 60 milliliters water for thesame period of time, thus demonstrating the water dispersibility of theInk Examples 2 and 3.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also thatvarious presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art which are also intended to beencompassed by the following claims. Unless specifically recited in aclaim, steps or components of claims should not be implied or importedfrom the specification or any other claims as to any particular order,number, position, size, shape, angle, color, or material.

The invention claimed is:
 1. A water dispersible phase change inkcomposition for printing on ophthalmic lenses comprising: a hydrophilicwax having at least one ethoxyl moiety; a low viscosity wax having atleast one hydroxyl group, wherein the low viscosity wax is miscible withthe hydrophilic wax; wherein the low viscosity wax is selected from thegroup consisting of stearyl alcohol, behenyl alcohol, and combinationsthereof; an optional stabilizer; and a colorant.
 2. The waterdispersible phase change ink composition of claim 1, further comprising:an amide.
 3. The water dispersible phase change ink composition of claim1, wherein the hydrophilic wax is an ethoxylated alcohol.
 4. The waterdispersible phase change ink composition of claim 1, wherein thehydrophilic wax is an ethoxylated alcohol of the formulaCH₃—(CH₂CH₂)_(n)—(CH₂CH₂O)_(m)—H wherein n is an integer and wherein mis an integer, and wherein n and m are each independently selected suchthat the total number of carbon atoms is from about 20 to about
 50. 5.The water dispersible phase change ink composition of claim 1, whereinthe low viscosity wax is a wax having a viscosity of from about 1 toabout 15 centipoise at a temperature in the range of from about 80° C.to about 120° C.
 6. The water dispersible phase change ink compositionof claim 1, wherein the low viscosity wax behenyl alcohol.
 7. The waterdispersible phase change ink composition of claim 1, wherein the amideis selected from the group consisting of monoamide, triamide,tetra-amide, and combinations thereof.
 8. The water dispersible phasechange ink composition of claim 1, wherein the amide comprises abranched triamide.
 9. The water dispersible phase change ink compositionof claim 1, wherein the stabilizer is present and is selected from thegroup consisting of aromatic amine, hindered amine, phenol, andcombinations thereof.
 10. The water dispersible phase change inkcomposition of claim 1, wherein the stabilizer is an aromatic amineantioxidant.
 11. The water dispersible phase change ink composition ofclaim 1, wherein the colorant is selected from the group consisting ofdyes, pigments, and combinations thereof.
 12. The water dispersiblephase change ink composition of claim 1, wherein the colorant comprisesa yellow dye.
 13. The water dispersible phase change ink composition ofclaim 1, wherein the colorant comprises a black dye.
 14. An ink jetprinter stick or pellet comprising a water dispersible phase change inkcomposition for printing on ophthalmic lenses, wherein the phase changeink composition comprises: a hydrophilic wax having at least one ethoxylmoiety; a low viscosity wax having at least one hydroxyl group, whereinthe low viscosity wax is miscible with the hydrophilic wax; wherein thelow viscosity wax is selected from the group consisting of stearylalcohol, behenyl alcohol, and combinations thereof; an optionalstabilizer, wherein the optional stabilizer, if present, is selectedfrom the group consisting of hindered amine, phenol, and combinationsthereof; and a colorant.
 15. The ink jet printer stick or pellet ofclaim 14, further comprising: an amide.
 16. The ink jet printer stick orpellet of claim 14, wherein the hydrophilic wax is an ethoxylatedalcohol.
 17. The ink jet printer stick or pellet of claim 14, whereinthe low viscosity wax is behenyl alcohol.
 18. The ink jet printer stickor pellet of claim 14, wherein the amide is selected from the groupconsisting of monoamide, triamide, tetra-amide, and combinationsthereof.
 19. The ink jet printer stick or pellet of claim 14, whereinthe colorant is a black dye or a yellow dye.